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Copper selenide is widely considered to be a promising candidate for high-performance flexible thermoelectrics; however, most of the reported ZT values of copper selenides are unsatisfactory at a relatively low temperature range. Herein, we utilized some wet chemical methods to synthesize a series of copper selenides. XRD, SEM and TEM characterizations revealed that CuSe, Cu3Se2 and Cu2−xSe were prepared successfully and possessed different morphologies and sizes. Based on the analysis of their thermoelectric properties, Cu2−xSe exhibited the highest Seebeck coefficient and lowest thermal conductivity among the three samples owing to its unique crystal structure. After being sintered at 400 °C under N2 atmosphere, the electrical conductivity of Cu2−xSe enhanced considerable, resulting in a significant improvement of its ZT values from 0.096 to 0.458 at 30 to 150 °C. This result is remarkable for copper selenide-based thermoelectric materials at a relatively low temperature range, indicating its brilliant potential in the field of flexible thermoelectric devices.

Fast charge transfer and lithium-ion transport in the electrodes are necessary for high performance Li–S batteries. Herein, a N-doped carbon-coated intercalated-bentonite (Bent@C) with interlamellar ion path and 3D conductive network architecture is designed to improve the performance of Li–S batteries by expediting ion/electron transport in the cathode. The interlamellar ion pathways are constructed through inorganic/organic intercalation of bentonite. The 3D conductive networks consist of N-doped carbon, both in the interlayer and on the surface of the modified bentonite. Benefiting from the unique structure of the Bent@C, the S/Bent@C cathode exhibits a high initial capacity of 1,361 mA h g−1 at 0.2C and achieves a high reversible capacity of 618.1 m Ah g−1 at 2C after 500 cycles with a sulfur loading of 2 mg cm−2. Moreover, with a higher sulfur loading of 3.0 mg cm−2, the cathode still delivers a reversible capacity of 560.2 mA h g−1 at 0.1C after 100 cycles.

Motivated by novel graphyne-like carbon nanostructure C68-GY, spin-polarized DFT calculations with dispersion-correction were performed to investigate the hydrogen adsorption capacity of Li decorated C68-GY nanosheet. The binding energy between Li and C68-GY was larger than the cohesive energy of bulk metal, indicating Li atoms would prefer to separately attached on C68-GY. The ab initio molecular dynamics simulation has been performed to confirm the stability of Li/C complex. When five Li atoms decorated on C68-GY, 14H2 molecules were captured. The maximum hydrogen storage density was 8.04 wt% with an average hydrogen adsorption energy of −0.227 eV per H2. The positively charged Li atoms aroused electrostatic field and induced the polarization of H2. It was notable to observe strong hybridization between the main peak of H-1s orbitals with Li below Fermi level, which was responsible for the enhancement of hydrogen binding energy, indicating its potential application on hydrogen storage.

Erosion control materials with long-term effective, economical and environmentally friendly properties play a critical role in controlling erodible and unstable sandy slopes deformed under rainfall. In this study, a novel cellulose-based curing agent was developed and applied as a sustainable sand fixation materisal. The novel cellulose-based curing agent was a dual-polymer composite material (DPCM), which was prepared by mixing two kinds of organic polymer materials: carboxymethyl cellulose (CMC) and polyacrylamide (PAM). The microstructure and composition of DPCM were characterized by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The adsorption kinetics of the curing agent on sand particles was discussed by fitting with pseudo-first-order and pseudo-second-order kinetic models. Water resistance and the compressive strength of the sand-fixing specimen at different curing ages were studied. Finally, the DPCM stabilization layer’s resistance to water erosion was investigated using a rainfall simulation test. The results demonstrated that the adsorption kinetic behavior of DPCM adsorbed on sand particles followed pseudo-second-order kinetics. Additionally, the interaction between the DPCM and sand particles was primarily hydrogen bonding, covalent bonds, and physical adsorption. The compressive stress was in the range from 53 to 915 kPa. Sandy slopes treated by DPCM showed excellent resistance to water erosion under a rainfall intensity of 120 mm/h.

For electrically conductive adhesives (ECAs), high electrical conductivity generally conflicts with excellent mechanical properties because electrical conductivity increases while desirable mechanical properties decrease with the increase in loading of conductive fillers or removal of lubricants on the silver filler surface. In this work, a method was developed to improve both the electrical conductivity and mechanical properties of the ECAs by introducing double bonds. Itaconic acid (IA) was used to replace the lubricant on the silver flake (Ag-F) surface, and acrylic acid (AA) was used as part of the ECA resin matrix. IA can replace the lubricant on the Ag-F surface, similar to other short-chain dibasic acids, to improve the ECA electrical conductivity. Furthermore, IA can be polymerized with AA to form covalent bonds between the silver flakes and the resin matrix, enhancing the mechanical properties of ECA. Compared with ECA filled with commercial silver flakes, the electrical conductivity of ECA filled with IA-treated silver flakes increased by ~ 21%, and the lap shear strength increased by ~ 29%.

The hydrogen storage capacity of yttrium decorated graphyne nanotubes is calculated using spin polarized DFT method. The stabilities, electronic properties and the structures of Y attachment on graphyne tube are investigated. It is revealed that Y can be separately adsorbed on graphyne tube with the binding energy of 6.76 eV and the clustering of metal atoms is hindered. The geometry optimization shows that Y atoms decorated graphyne tube can capture 42H2 molecules through Dewar-Kubas like interaction and the polarization under the electrostatic potential formed by Y and graphyne tubes. The weight percent capacity is 5.71 wt%, with an average hydrogen adsorption energy of −0.153 eV per H2, indicating its potential application on hydrogen storage candidates.

The chemisorption and catalysis of lithium polysulfides (LiPSs) are effective strategies to suppress the shuttle effect in lithium-sulfur (Li-S) batteries. Herein, multisize CoS 2 particles intercalated/coated-montmorillonite (MMT) as an efficient sulfur host is synthesized. As expected, the obtained S/CoS 2 @MMT cathode achieves an absorption-catalysis synergistic effect through the polar MMT aluminosilicate sheets and the well-dispersed nano-micron CoS 2 particles. Furthermore, efficient interlamellar ion pathways and interconnected conductive network are constructed within the composite host due to the intercalation/coating of CoS 2 in/on MMT. Therefore, the S/CoS 2 @MMT cathode achieves an outstanding rate performance up to 5 C (~548 mAh·g -1 ) and a high cycling stability with low capacity decay of 0.063 and 0.067% per cycle for 500 cycles at 1 and 2 C, respectively. With a higher sulfur loading of 4.0 mg·cm -2 , the cathode still delivers satisfactory rate and cycling performance. It shows that the CoS 2 @MMT host has great application prospects in Li-S batteries.

Catalytic oxidation of formaldehyde (HCHO) at ambient temperature is an effective method for indoor HCHO removal. In this study, Ni/Co-Layered double hydroxides (LDHs) with different molar ratios were successfully synthesized via a one-step hydrothermal method. Their structure and morphology were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Brunauer–Emmett–Teller (BET)-specific surface area, X-ray photoelectron spectroscopy (XPS), and H2 temperature-programmed reduction (H2-TPR), respectively. The catalytic activity results show that Ni/Co-LDHs with the Ni/Co ratio of 1:2 exhibited enhanced activity for HCHO decomposition. The removal efficiency of indoor HCHO was up to 99.7% at ambient temperature, and it remained highly stable without any obvious deactivation even after a reaction time of 800 min. The abundant hydroxyl groups were favorable for catalytic activity, which could not only enrich the adsorption of HCHO on the surface of catalysts, but also directly react with HCHO to obtain CO2 and H2O. Moreover, the redox cycles of Ni3+/Ni2+ and Co3+/Co2+ would provide more reactive oxygen species and therefore promote catalytic reaction. This work can provide a new insight into LDH-based catalysts for low-concentration HCHO removal in practical application.

Thiol-ene click reactions are more oxygen tolerant alternative to the conventional (meth)acrylate chemistry that is frequently used for the rapid production of photopolymerized networks with numerous desirable properties. To attain a high curing efficiency while maintaining the advantages of thiol-ene systems, a castor oil-based hyperbranched urethane acrylate was employed in this work as a primary oligomer for UV-curable coating formulation. Subsequently, a tetrathiol monomer (PETMP) was introduced into the coating formulation to obtain a thiol-ene system. The effects of PETMP loadings on the UV-curing kinetics and final polymer properties were systematically investigated. Consequently, thiol-ene based films with excellent flexibility and water resistance were obtained as a result of the high efficient thiol-ene photopolymerization. The double bond conversion of the thiol-ene system was found to increase with the addition of more PETMP. Impressively, with the incorporation of 5 wt% PETMP, the resultant UV-cured film had the best acid resistance and exhibited a double bond conversion of 93.6%, a pencil hardness of 6H, a water absorption of 0.76%. Additionally, all of the prepared films were completely transparent and possessed good microstructures. These thiol-ene based films may provide insight into the preparation of high-performance UV-curable coatings with excellent flexibility.

Fluoride removal from aqueous solution by adsorption using fly ash cenospheres (FAC) modified with paper mill lime mud (LM) as composite adsorbent had been investigated. The characterization of FAC and composite adsorbent were analyzed by Scanning electron spectroscope (SEM), Energy dispersive spectrometer (EDS), Brunauer emmett teller (BET) and Fourier transform infrared (FTIR), which demonstrated that the porous structure of composite adsorbent was obtained after surface modification. Adsorption of fluoride on modified fly ash cenospheres was fitted with pseudo-second-order model and Langmuir model. Response surface methodology (RSM) was employed to investigate the effects of F− concentration, pH, adsorbent dosage and temperature on the removal efficiency. Analysis of variance (ANOVA) was used to test the adequacy of the mathematical models. The Nonelectrostatic model of modified fly ash cenospheres adsorbing fluoride was built through the Generalized composite method, indicating that two inner-spherical complexes, ≡SF and ≡SOHF−, were formed in the adsorption process by means of the ligand exchange and surface complexation. Optimization of the adsorption conditions enabled the realization of the practical needs for fluoride contaminated water.

The structural, elastic, mechanical and thermodynamic properties of α, β, and h-CuGaO2 were investigated based on first-principles calculations. The obtained lattice parameters were in good...

The issue, high glass-forming abilities (GFAs) in solute-absent multicomponent metallic glasses (MGs), has been investigated by systematic experimental measurements coupled with theoretical calculations in the Cu34Zr14Ti36Pd16 quaternary alloy. It is found that the synergetic contribution of some atomic- and cluster-level structural features leads to the high GFA in this quaternary composition. At the atomic scale, Pd and Ti addition decreases the size gaps between Cu and Zr atoms, and increases the atomic packing efficiency; at the cluster scale, there are more icosahedral or icosahedral-like local structures, and the cluster regularity is enhanced because of the optimization of both topological and chemical distributions in clusters. The present work provides an in-depth understanding of GFAs in multicomponent alloys, and will shed light on the development of more MGs with high GFAs.

Cross-linked sustained-release polycarboxylate superplasticizers (SPs) are superior alternative to the comb-type polycarboxylate SPs due to they offer both a high fluidity and a good retention effect for concrete slurry. In this context, a series of cross-linked polycarboxylate superplasticizers were synthesized using acrylic acid, methylallyl polyoxyethylene ether and four different cross-linkers containing ester groups, respectively. The key difference among these four cross-linkers is their molecular weights because they each possessed the different ethoxy content. The fluidity and fluidity retention tests, adsorption performance and scanning electron microscope tests showed that the cross-linked superplasticizers offered good dispersing effects and excellent slump performance. Excitingly, the maximum flow reached up to 394 mm at a water-cement ratio of 0.35 and this high fluidity could be simultaneously maintained for 2 h, which facilitated concrete transport over long distances, therefore improving the practical workability of concrete. Furthermore, it was found that the superplasticizers derived from cross-linkers with higher ethoxy group contents provided cement paste samples with improved fluidity. Evaluation of the hydration heat and setting time demonstrated that the cross-linked polycarboxylate superplasticizers could delay the hydration of cement and the final setting time had been extended by 4 h in comparation with blank samples. After 3, 7 and 28 d, the compressive strength of the cement mortar was improved with increases of molecular weight of the cross-linker in the cross-linked superplasticizers due to the elevation of ethoxy content.

Synthesis, characterization, and coating performance of castor oil (CO)-based waterborne hyperbranched polyurethane acrylate (WHPUA) emulsions are highlighted in this work. Herein, a second-generation CO-based hyperbranched polyester (C20) was synthesized by introducing the renewable CO as a B3 core and dimethylolpropionic acid as an AB2 monomer via a pseudo-one-pot condensation procedure. Three types of CO-based WHPUA emulsions were prepared through the addition of the hyperbranched C20 with maleic anhydride (MA) and the isocyanate-bearing semiadduct (IPDI-HEA) at different MA/IPDI-IH molar ratios without the addition of any emulsifiers. The prepared emulsions were further formulated into UV-curable coating formulations and exposed to a medium-pressure mercury lamp. Consequently, the obtained UV-cured coatings exhibited outstanding adhesion performance, excellent transparency, and an acceptable degree of final double bond conversion. Owing to a relatively low concentration of hydrophilic units and a large number of acrylate functionalities in the waterborne oligomer, the obtained films were endowed with high crosslinking density and low hydrophilic nature, thus producing enhanced tensile strength, pencil hardness, water resistance, and chemical resistance. Due to their combination of renewable materials, a waterborne system and a UV-curing technique, these CO-based WHPUA emulsions offer promising opportunities to be used as environmentally friendly coatings.

Photoresponsive complex emulsions are prepared in a three-phase system consisting of two oils: hexane (H) and perfluorooctane (F). An aqueous solution of a mixed surfactant of fluorosurfactant, F(CF2)x(CH2CH2O)yH (Zonyl FS-300), and a synthesized light-responsive surfactant, 2-(4-(4-butylphenyl)diazenylphenoxy)ethyltrimethylammonium bromide (C4AZOC2TAB) was employed as the continuous phase. Complex emulsions with various geometries were prepared by one-step vortex mixing and a temperature-induced phase-separation method. It was noticed that the topology of the complex emulsion was highly dependent on the mass ratio of Zonyl FS-300/C4AZOC2TAB. Light microscopy images showed that phase inversion from an H/F/W- to an F/H/W-type double emulsion via a Janus emulsion was achieved by gradually increasing the mass ratio of C4AZOC2TAB/Zonyl FS-300. Upon UV/blue light irradiation, the topology of complex emulsions was turned to switch from an F/H/W double emulsion to a Janus emulsion to an entirely inverted H/F/W d...

Block copolymers (BCPs) have stimulated widespread research interest due to their applications as facile templates in the fabrication of optimized thermosets with micro– or nanostructured morphologies. In the present work, a novel block copolymer was obtained from a commercial poly(styrene-block-butadiene-block-styrene) (SBS) triblock copolymer precursor by a two-step process including reaction with hydrogen peroxide in a water/dichloroethane biphasic system to achieve an epoxidized derivative with a 46 mol% degree of epoxidation (thus denoted as eSBS46), which was then followed by reaction with 1-(2-aminoethyl)piperazine (AEP, thus yielding eSBS46-AEP) as a reactive functional group that was incorporated to prepare nanostructured epoxy thermosetting blends. As a result of the oxirane ring-opening achieved (to a conversion degree of 10 mol%) by reaction with AEP, the nanostructured morphology was converted from spherical micelles in the case of eSBS46 to branched wormlike micelles for eSBS46-AEP. ...

A novel waterborne polyurethane (WPU) resin with low gloss and micro-roughness was synthesized by the prepolymer and self-emulsification method. It was achieved by introducing multi-hydroxyl castor oil and reactive bisphenol A-type epoxy E-44 or E-51 resin to polyurethane prepolymer to form a cross-linking network structural waterborne polyurethane emulsion, which demonstrated the distinctive characteristic of the shear-thinning pseudoplastic fluid with a yield stress. The chemical structures and rough surface morphologies of the WPU films were characterized by FTIR-ATR, LCRS, AFM, SPMS and SEM, respectively. The specular gloss values at 20°, 60° and 85° incident angles were measured, and the values of different kinds of roughness parameters were obtained. The relationship between the gloss and the castor oil content was also discussed in detail. In general, this WPU resin endowed the film with micro-roughness, moderate hardness and good adhesive strength, making it very prospective in substitution for the traditional low gloss coatings.

A novel environmentally friendly method was developed to fabricate hollow core–shell conductive nanoparticles using a natural and nontoxic material, nanocrystalline cellulose (NCC), as the template. The NCC used in this study has nano-scale rod-like structure. After the oxidization to dialdehyde cellulose, the insulated NCC was functionalized by poly(dopamine) (PDA) in weakly alkaline conditions through Schiff base reaction and self-polymerization. The Schiff base can be hydrolyzed in an aqueous acetone solution via ultraviolet radiation so that the hollow structure constructed. This structure not only strengthened the mechanical properties but also provided more active sites for silver deposition. Utilizing the chelating ability of the catechol groups in PDA, electroless plating method was used to form the silver coating layer. Scanning electron microscope and Dynamic Light Scattering measurements indicated that these nanoparticles (NPs) had well-defined morphology and a mean diameter of 100–120 nm. Moreover, these prepared Ag–DA–NCC0 NPs exhibited excellent conductivity. Their electrical resistivity reached 0.2 mΩ·cm, which is much higher than that of many other conductive particles used in conductive adhesive.

Castor oil (CO) based hyperbranched urethane acrylates (HBUAs), namely C10-IH and C20-IH, were synthesized by modifying the hydroxyl groups of first (C10)- and second (C20)-generation of CO-based h...

A series of low gloss waterborne polyurethane acrylate (WPUA) hybrid emulsions with different weight ratios of hard/soft monomers of acrylic monomers were synthesized successfully. Compared with the traditional low gloss coatings that achieve low gloss effects by adding a large number of pigments, fillers or both to roughen the surfaces, the low gloss effect of these WPUA emulsions was achieved through the formation of self-roughed surfaces during film formation with zero loading of extraneous dulling agent. Gloss levels could be as low as 3 units at 60° incident angle. The chemical structures of these WPUA films were characterized by nuclear magnetic resonance carbon spectroscopy ( 13 C NMR), Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). The rough surface topographies of these WPUA films were observed by scanning electron microscopy (SEM). The particle size distributions of these WPUA emulsions were analyzed by DLS measurement. The polymeric phase separation behaviors of these WPUA films were assessed by DSC analysis. In general, the WPUA emulsions that afforded films with good hardness, good adhesion strengths and excellent thermal stabilities, showed a great advantage in applications of low gloss aqueous coating.

Graphene is an important class of carbon-based materials that exhibits excellent thermal conductivity along its layers. In order to construct a 3D thermal transport material, herein, SiO2@C was successfully inserted into the reduced graphene oxide (rGO) layers to enhance its axial thermal transport performance via vacuum-assisted electrostatic self-assembly and pyrolysis processes. The formed rGO-SiO2@C composite exhibits an enhanced axial thermal conductivity of 6.65 W/(m*K) and an in-plane thermal conductivity of 36.54 W/(m*K). Moreover, it also displays good electromagnetic shielding properties, with the high total shielding effectiveness (SET) value of 45.59 dB, and an ultralow shielding effectiveness reflection (SER) value of 2.72 dB. Our work provides a simple method to construct a hybrid as a 3D conductive and thermal conductive network.

Magnesium phosphate cement-fly ash (MPC-FA) has been synthesized as a new cutoff wall material to control lead pollution in groundwater. A series of experiments were conducted to investigate its properties including adsorption, mechanical performances, morphologies, microstructure and migration of Pb(Ⅱ) through the magnesium phosphate cement-fly ash cutoff walls. X-ray microcomputed tomography was used to get the microscale three-dimensional real geometry images of the cutoff walls. The internal structural parameters were analyzed through digital image processing technology. Lattice Boltzmann method (LBM) was employed to simulate the hydraulic conductivity and three-dimensional velocity fields distribution of cutoff walls. The optimized fly ash ratio (in mass) of cutoff walls was 40%, and the sodium dihydrogen phosphate/monopotassium phosphate molar ratio was 1:1. The compressive strength and flexural strength during 14 days were 23.2 MPa a nd 5.6 MPa, respectively. The laboratorial hydraulic conductivity of MPC-FA was 1.22 × 10−9 m/s and the theoretical maximum adsorption capacity was 467.87 mg/g. The pore-network model showed that the connected porosity of MPC-FA was 14.45%, and the most of the pores and throats in cutoff walls were microflow paths (radius ≤ 12 μm). The hydraulic conductivity simulated by LBM basically coincided with the measured results, and the velocity fields indicated that the flow paths were tortuous and complex. Under different breakthrough concentration standards, the penetration of Pb(Ⅱ) at initial concentration of 4000 mg/L through cutoff walls with thickness of 0.6 m, 1 m, 1.2 m, 1.5 m needed 8–10, 22–28, 31–41 and 49–64 years, respectively. The model obtained by Visual MODFLOW numerical simulation showed that the contaminant plume of Pb(Ⅱ) was controlled after 7400 days in the polluted site with MPC-FA cutoff walls, which supported that the MPC-FA met the requirements for good control of Pb(Ⅱ) in the lead-contaminated sites.

This paper reports on a novel self-matte or bulk-matte waterborne polyurethane coating composite with inherently extremely low gloss. The coating composite was comprised of a siloxane-containing waterborne polyurethane (SPU) resin and a crosslinked waterborne polyurethane (CPU) resin. The CPU resin was mainly responsible for fabricating the micro-rough surface of the film, which was achieved by a crosslinking reaction between the waterborne polyurethane and bisphenol A-type epoxy E-44 resin. The SPU resin was used to improve the comprehensive properties of the film, which was ascribed to the addition of silane coupling agent KH792. Compared with traditional matte coatings, this coating composite made it possible to avoid high loadings of matting agent and to arrive at highly flexible low-gloss finishes. Gloss levels of as low as a few tenths of a percent, even at high incidence angles, have been achieved with zero loading of extraneous dulling agent. The chemical structures of the SPU and CPU resins were characterized by FTIR-ATR and NMR spectra. The micro-rough topographies and surface rough degrees of the SPU, CPU and their 50%/50% composite films were measured by SEM and MSP, respectively. The particle sizes and particle morphologies of the SPU and CPU resins were imaged by TEM. Finally, the comprehensive properties of the SPU, CPU and their 50%/50% composite resins were evaluated, including the water contact angle, film transparency, tensile strength and storage stability.

A peak aged (T6 heat treatment: 743 K /1.5 h + 393 K/24 h) Al-Zn-Mg-Cu alloy was subjected to compression tests at different strain rates from 1.0 × 10−3 s−1 to 5.0 × 103 s−1. The yield strength of the Al alloy is increasing with strain rates from 1.0 × 10−3 s−1 to 4.0 × 103 s−1and is decreasing with increasing strain rate from 4.0 × 103 s−1 to 5.0 × 103 s−1 showing strain rate sensitivity (SRS). A large number of Al3Zr, GP zones, η’, T (Al2Mg3Zn3) and S (Al2CuMg) precipitates are present in the Al alloy after compression at 1.0 × 10−3 s−1 and Al3Zr, η’, η, T and S phases are dominant after high strain rate compression from 3.5 × 103 s−1 to 5.0 × 103 s−1. The precipitates average size is increased after compression at 1.0 × 10−3 s−1. High strain rate compression leads to the growth of precipitates and overlapping. Coarse precipitates are mainly found along the grain boundaries and dislocations. The increasing SRS with increasing strain rates up to 4.0 × 103 s−1 owes to the growth of precipitates which are hindering dislocations motion and generating more dislocations. Increasing strain rates to 5.0 × 103 s−1, the coarse precipitates are no longer effective in pinning dislocations, leading to a decrease in yield strength and a negative SRS value.

Through inserting SiO2@Au into the reduced graphene oxide (rGO) layers, the rGO-SiO2@Au composites were prepared via the vacuum-assisted electrostatic self-assembly method. The obtained composites exhibit excellent electromagnetic interference (EMI) shielding effectiveness due to the successful construction of multi-nanocavities (spherical SiO2 cavities and layered air cavities between rGO), multi-reflection interfaces (rGO and Au shell) and continuous conductive network (rGO-Au-rGO). Among them, the total shielding effectiveness (SET) of the composites with 75.78 wt% SiO2 and 19.38 wt% rGO can reach 38.4 dB at 18 GHz. Thereinto, the shielding effectiveness absorption (SEA) is 36.4 dB, 1.3 and 13.5 times higher than that of rGO and SiO2@Au. And the shielding effectiveness reflection (SER) is always below 5 dB from 1 to 18 GHz, much lower than that of rGO (about 15 dB). Further studies found that the SEA values were enhanced at 12.6 GHz and 6.2 GHz due to the construction of cavities and location of Au nanoparticles between the rGO layers. This study provides a simple and mild method to prepare high-performance thin-layered materials with applications in the field of EMI absorption shielding.

For various applications, it is essential to enhance the colloidal stabilization of carbon nanotube (CNT) dispersions. Here, the polymers with carbazole pendants of poly(4-(N-carbazolyl)methylstyrene-bl-poly(ethylene glycol) methyl ether methacrylate) (PCMS5-b-PAPEG73 and PCMS16-b-PAPEG43) and PCMS30, synthesized by reversible addition–fragmentation chain transfer (RAFT) polymerization, were used for noncovalent functionalization of multiwalled carbon nanotubes (MWCNTs) in tetrahydrofuran (THF), offering efficient colloidal stabilization. Meanwhile, the adsorption of polymers onto MWCNTs was investigated. The results showed that the MWCNTs decorated with these three polymers in THF exhibited different colloidal stabilization and adsorption capacity. Moreover, the MWCNT dispersions could be stabilized for days and their colloidal stabilization elevated with the increase of polymer concentrations. The block copolymer PCMS16-b-PAPEG43 exhibited the optimal adsorption and dispersion capability for MWCNTs. The...

In this study, novel macro porous Ni2+-imprinted chitosan foam adsorbents (F-IIP) were prepared using sodium bicarbonate and glycerine to obtain a porogen for adsorbing nickel ions from aqueous solutions. The use of the ion-imprinting technique for adsorbents preparation improved the nickel ion selectivity and adsorption capacity. We characterised the imprinted porous foam adsorbents in terms of the effects of the initial pH value, initial metal ion concentration, and contact time on the adsorption of nickel ions. The adsorption process was described best by Langmuir monolayer adsorption models, and the maximum adsorption capacity calculated from the Langmuir equation was 69.93mgg-1. The kinetic data could be fitted to a pseudo-second-order equation. Our analysis of selective adsorption demonstrated the excellent preference of the F-IIP foams for nickel ions compared with other coexisting metal ions. Furthermore, tests over five cycle runs suggested that the F-IIP foam adsorbents had good durability and efficiency.

The high flexibility and adaptability of the soft actuator have attracted wide attention. However, under the stimulation of the external environment, the complex and controllable movement of materials remain a challenge. In this work, we make a bilayer composite film simply and quickly by depositing silicone rubber (Ecoflex00-30) on the side of the plant parchment. It spontaneously controls deformation and responds sensitively in the water. This bilayer composite film exhibits a good stable actuation effect and reversibility in a humid environment or in water. We cut the strips of plant parchment into different fiber directions and control the lateral gradient in the thickness direction to achieve complex and controllable motion (bending, S-shaped, -shaped and spiral). Inspired by the plant tendrils, we design and built a soft gripper that can achieve 30 times its own weight in the water, demonstrating promising bioinspired applications.

Understanding the structure–property relationship of polyurethane (PU) binders is of critical importance in the construction engineering applications. A series of rapid room temperature-curable PU binders were prepared using polyoxypropylene glycol as the soft segments, along with polymethylene polyphenylene isocyanate and 4,4′-methylene-bis(2-chlorobenzenamine) as the hard segments. This work investigated the influence of the hard segment content (40 wt%, 45 wt%, and 50 wt%) and the soft segment molecular weight (1000 g/mol, 2000 g/mol, 3000 g/mol, and 4000 g/mol) on the microphase structure of the PU binders. Their influence on the compressive behaviors, flexural behaviors, impact strengths, and slant shear strengths of the PU-based polymer concretes was also investigated. Structural characterization revealed that increasing either the hard segment content or the larger soft segment molecular weight effectively enhanced hydrogen bonding as well as microphase separation. Our results also demonstrated that a higher hard segment content resulted in better mechanical performance and shorter pot life. In addition, the PU-based polymer concrete using 2000 g/mol polyoxypropylene glycol reached optimal mechanical performance when the hard segment was held constant. Hence, varying the hard segment content and soft segment length can be an effective method to adjust the engineering performance of PU-based polymer concrete.

It is still a challenge to disperse yellow iron oxides in organic media due to their susceptible aggregation, which limits their application in ceramic material area. In order to achieve colloidal stabilization in organic liquid, yellow iron oxides were dispersed in ethanol with p[methyl methacrylate-r-butyl methacrylate-r-N-(3-dimethylaminopropyl) methacrylamide] random copolymers (PMBAs) based on amino groups as anchoring groups and alkyl as solvent chains by reversible-addition fragmentation chain-transfer radical (RAFT) polymerization. The effect of PMBAs on viscosity, rheological properties and dispersion stability was investigated. In the presence of PMBAs, yellow iron oxide dispersion performed excellent colloidal stability and low viscosity with high solid loadings. Furthermore, it is suggested that PMBAs have outstanding dispersion ability, retarding yellow iron oxides aggregating and keeping it stable for more than 60 days at ambient temperature. This study reveals that PMBAs might find promising application in material dispersion area.

Self-matt coating of waterborne polyurethane (WBPU) was synthesized by combining prepolymer and self-emulsification methods. The emulsion was fabricated from both hydroxy carboxylic acid and aminosulfonic acid types of hydrophilic chain-extending agents, in which the 2-[(2-aminoethyl) amino] ethane sulphonate sodium (AAS salt) was produced in laboratory. This emulsion demonstrated an excellent matt performance without the addition of extra matting agents after filming. Four different kinds of surface properties were measured on the film: the specular gloss (60° gloss meter), the contact angle (CA), the surface roughness degree (3D Surface Profilometer), and the topography of the coatings surface (SEM). The results showed that tons of spherical particles with diameter in a few micrometers were aggregated on the film surface. The effect of the roughness parameters (R a and R q ) and the average particle size of the emulsions on the specular gloss degree were probed. The research indicated that the emulsion with average particle size in the range of 2.5–3.0 µm and, meanwhile, the film with roughness parameters R a and R q both greater than 1 µm could attain the best matt effect. The WBPU emulsions showed good physical and mechanical properties, and were introduced into wood varnish for matting purpose.

At present, several researchers mainly focus on the synthesis of new micro-cross-linking structure, or explore the effect of cross-linkers with different molecular weight and similar structure on the performance of cross-linked polycarboxylate superplasticizers. In order to explore the influence of the different molecular structure of the cross-linker on the performance of polycarboxylate superplasticizers, two kinds of cross-linked polycarboxylate superplasticizers were synthesized in this study. These two superplasticizers incorporated either a linear cross-linker triethylene glycol diethyl ether or a cyclic cross-linker 3,9-divinyl-2,4,8,10-tetroxyspiro[5,5] undecane as one of the monomers. Then the polymers were respectively coded as SPT and SPD. Furthermore, the dispersion performance of the cross-linked polymers was evaluated by cement slurry fluidity tests and scanning electron microscopy (SEM) characterization. Consequently, cementitious mixtures incorporating SPT had better dispersibility than those incorporating conventional comb-type polycarboxylate superplasticizers (SPC) and SPD. In addition, the XRD, thermogravimetric analysis (TGA), hydration heat, and setting time tests confirmed that SPT exhibited a stronger retardation effect on cement hydration than that was provided by SPD. It was also found that SPT enhanced the compressive strength of concrete, compared to SPC and SPD. This study provides a reference for the development of cross-linked polycarboxylate superplasticizer.

Groundwater barriers are extensively used for absorbing and blocking heavy-metal contaminants in groundwater. Experiments were conducted to characterize and evaluate the adsorption and migration of Pb(II) through a novel fly ash-bentonite blocking wall. Laboratory analyses included column diffusion, digestion and centrifuge tests to determine the permeability, adsorption, diffusion, and form of Pb(II). By diffusion and column tests, the effective diffusion coefficient of the blocking wall was estimated to be 4.47 × 10−10 m2 s−1 and the stable seepage velocity of Pb(II) was obtained to be 3.55 × 10−9 m s−1. These tests were used to determine the service life of the fly ash-bentonite mixture, which is shown to be superior to other bentonite mixtures, including silt, loess-silt, and kaolin. The service life is a function of the thickness, retardation factor, design breakthrough concentration, and upstream head.

A modified plastic concrete cut-off wall was synthesized using different mass ratios of silica fume (0–21.3%) and constant cement content (8%) based on the conventional soil-bentonite cut-off wall. The slump test, hydraulic conductivity and mechanical performance were analysed to determine the optimal material ratio. The hydraulic conductivity of the optimal sample could meet the anti-seepage requirement (~10-9 m/s). The amended plastic concrete cut-off wall could obtain the appropriate compressive strength (0.896 MPa) and a low elastic modulus (1244.5 MPa). The characterization of the clayey soil materials and modified plastic concrete cut-off walls were analysed by X-ray diffraction (XRD) methods, which demonstrated that the clayey soil mainly contained quartz and feldspar (anorthite). The pozzolanic reaction between the silica fume and calcium hydroxide and the refinement of the pore structure could increase the compressive strength and reduce the hydraulic conductivity. Microscale three-dimensional real geometry images of the modified plastic concrete for cut-off walls were obtained from X-ray microcomputed tomography. The internal structural parameters were analysed through pore-scale modelling. The hydraulic conductivity and velocity fields were simulated using the lattice Boltzmann method. The results showed that most of the pores and throats in the modified plastic concrete for cut-off walls were micropores and microflow paths (diameter ≤ 5 μm), and the connected porosity was approximately 25.89%. The simulated hydraulic conductivity was in good agreement with the measured value, and the velocity fields indicated that the microflow paths were tortuous and complex. The silica fume-modified plastic concrete for cut-off walls enabled the realization of the requirements for good control of the water seepage in hydraulic engineering construction applications at a low cost.

A series of semi-gloss waterborne polyurethane-polyacrylate (PUA) hybrid dispersions containing different weight ratios of styrene/butyl acrylate monomers were first synthesized by solution polymerization and then phase inversion. The average particle size of PUA dispersions particle was analyzed by dynamic light scattering (DLS) measurement. Its core-shell morphology was characterized by transmission electron microscopy (TEM), whose structure was also confirmed by FTIR and nuclear magnetic resonance carbon spectroscopy (13C-NMR). The surface morphology of the PUA films was observed by scanning electron microscopy (SEM). The thermal properties of the PUA films were characterized by differential scanning calorimetry (DSC) analysis, and the core-shell hybrid latex films showed phase separation behaviors. The results showed that the PUA films had a self-rough surface, and exhibited excellent adhesion strengths and good hardness.

This work investigates the fabrication and improvement of the polyurethane (PU)-based polymer concrete (PC) for rapid cementitious runway repair. To overcome the low strength and moduli typically exhibited by the PU binders, the ground glass fiber (GGF) particles were employed to enhance the final mechanical parameters of the PU-based PC. A series of laboratory characterization and mechanical tests were conducted to analyze the structure and properties of the PU/GGF composites and the PU-based PC. The experimental results ascertain the enhancing mechanism of GGF particles, and a suitable GGF content is obtained. The present work reveals that the GGF particles can be a reinforcing filler for the PU-based PC.

A novel blocking wall was synthesized using fly ash and bentonite with strong adsorption capability. The optimized material ratio of the blocking wall was determined by penetration tests, shear tests and adsorption tests. The morphologies and stabilities of blocking wall samples with optimized material ratio were investigated by scanning electron microscopy (SEM), energy spectrum analysis (EDS), and erosion tests, the adsorption capability of blocking wall with optimized material ratio was investigated by adsorption kinetic and isotherm tests, the migration and penetration time of Cd pollutants in blocking wall with optimized material ratio were investigated by penetration tests and numerical simulations. Results indicated that the optimized fly ash/bentonite ratio (in mass) of blocking wall was 5:1. The permeability coefficient was 1.11 × 10−8 m s−1 and the maximum adsorption rate was 98.38%. Meanwhile, Cd2+ adsorbed on the blocking wall homogeneously; the alkali corrosion resistance of the blocking wall was higher than its acid corrosion resistance, and its resistance to organic pollutants and solutions with high Cd2+ concentrations were high. The adsorption process can be described by the Quasi-first-order kinetics and the Freundlich equation. Specifically, the overall adsorption efficiency was simultaneously affected by liquid membrane diffusion and particle diffusion and the adsorption process is an endothermic one dominated by physical adsorption. Additionally, Cd2+ penetration through the wall was dominated by molecular diffusion. The variation of permeability coefficient was inversely proportional to the initial concentration of Cd2+. The penetration of Cd2+ at initial concentration of 500 mg L−1 through the blocking wall needs 40 years.

A new series of poly (AA-co-β-CD-A-co-TPEG) (PACDs) copolymers were prepared by the copolymerization of a novel monovinyl β-cyclodextrin monomer (β-CD-A), acrylic acid and isoprenyl oxy polyethylene glycol (TPEG-2400), which could be used as superplasticizers and shown excellent dispersion ability. Therefore, this work mainly investigated the adsorption behavior, dispersing properties as well as hydration behavior of cement pastes. Optical microscopy was employed to describe dispersing performance. X-ray diffraction (XRD) and TGA/DTG were utilized to account for the cement hydration process. We found that the PACDs with β-CD-A exhibited outstanding dispersion ability. In addition, the performances of the PACDs were monitored by evaluating the setting time and fluidity of the cement paste. The results clearly shown that the setting time was longer and slump loss was smaller than that of PACD0 that without β-CD-A. Therefore, PACDs with the proper content of β-CD pendants had excellent performances due to the steric hindrance of the CD moieties.

A high-efficiency hollow BiOCl@CeO2 heterostructured microspheres with type-II staggered-gap type was successfully synthesized by precipitation-hydrothermal process loaded with BiOCl nanoparticles on CeO2 microspheres. XRD, FT-IR, EDS, SEM, HRTEM and XPS results show that the prepared materials have good crystallization, morphology and retain hollow spherical structure of CeO2. Batch experiments indicate that the photocatalytic performance of BiOCl@CeO2 towards Tetracycline (TC) is superior to pure BiOCl or CeO2 owing to the distinctive hollow structures and the formed heterostructure between BiOCl and CeO2. Cyclic experiment exhibits that the optimal BiOCl@CeO2 photocatalyst can still photodegrade more than 80% of TC in 120 min after 4 cycles. Additionally, the reactive oxidation species (ROS) trapping experiments reveal that the critical ROS include photogenerated holes (h+) and superoxide radical anions ( O2−). Finally, the possible degradation pathways of TC and enhanced photodegradation mechanism was systematically discussed. On this basis, the hollow BiOCl@CeO2 heterostructured microspheres provide a new alternative with great potential in efficient visible-light-driven photodegradation of persistent organic pollutants.

The mechanical, vibrational and thermodynamic characteristics of Ni2Ta were systematically investigated by means of density functional theory. The fully relaxed structure parameters were agreed well with the available experimental measured datas and published theoretical results. The single crystal elastic constants， polycrystalline modulus, Possion's ratio σ and Vickers hardness Hv were obtained. The anisotropic characters were studied by plotting the 3D surface contour of shear modulus and Young's modulus. Using the finite displacement method, the phonon dispersion curves and the phonon density of states were reported for the first time. The infrared-active and Raman phonon modes at the Г point were assigned and discussed. Finally, the thermodynamic characteristics such as isochoric specific heat capacities Cv and Debye temperature θD were predicted by the phonon density of states. Based on these exceptional properties, it was expected that Ni2Ta could be a promising intermetallic compound with high temperature and corrosion resistant performance.

Graphene quantum dots (GQDs) are regarded as promising materials in building biocompatible nanodevices. This paper puts forward a protocol to fabricate amine functionalized graphene quantum dots (afGQDs) by tailoring and exfoliating multilayered ammonia reduced graphene oxide (NH2-G) into afGQDs through a Hofmann rearrangement. The principle on how a Hofmann rearrangement assists in tailoring and exfoliating of NH2-G sheets into afGQDs was posited. The size distribution of afGQDs was tuned by a simple but efficient method based on the adjustment of sodium hypobromite dosage, accompanied by hydrolysis and filtration. The afGQDs emitted broad spectral wavelengths photoluminescence (PL) with two peaks centered at 430 and 510 nm, attributed to unmodified graphene oxide quantum dots and the amine group respectively.

Two new flexible cardanol-based epoxy curing agents with cross-linkable thiourea groups ([2-(2-amino-ethylamino)-ethyl]-thiourea of modified cardanol and [2-(2-amino-ethylamino)-ethyl]-thiourea of modified cardanol 2,3-dihydroxy propyl ether, ETC and TCP for short, respectively) were synthesized using a Mannich reaction. The structure of the prepared curing agents was analyzed by a nuclear magnetic resonance (NMR) and Fourier transform infrared spectroscopy (FT-IR). The curing kinetics of ETC (or TCP) cured diglycidyl ether of biphenyl A (DGEBA) epoxy resins was investigated using the Kissinger, Flynn–Wall–Ozawa and Crane methods by non-isothermal differential scanning calorimetry (DSC). Thermal properties of the cured epoxy resins were evaluated with thermogravimetric analysis (TGA) and DSC. The morphology and mechanical properties of the cured epoxy resins were also studied. The results showed that the epoxy curing agents had a high-reactivity and a low-viscosity, especially at low temperatures. The activation energy of ETC/DGEBA and TCP/DGEBA calculated by the Kissinger method were 53.6 and 60.5 kJ mol−1, respectively. The toughness of the cured epoxy resin was noticeably improved by the introduction of two new flexible curing agents. The glass transition temperature (Tg) decreased with the introduction of cardanol-based curing agents in an epoxy resin system. In addition, the cured epoxy materials exhibited good mechanical properties.

Simultaneously using sulfonic and carboxylic acid as hydrophilic chain-extending agents, a new type of solvent-free and chemical matt waterborne polyurethane resin was prepared and investigated. The chemical structure containing urethane and urea groups in this novel carboxylate/sulfonate type of waterborne polyurethane (CSWPU) resin was confirmed by FTIR, 1H and 13C NMR spectra. An obvious advantage for the environment is that, unlike the traditional synthetic method for waterborne polyurethane, the reactive system doesn't need any organic solvent to reduce the viscosity of the prepolymer in the process of prepolymerization. In addition, the gloss extinction was generated by the drying process of the resin itself, without the requirement of any matting agents. 3D-AFM images indicate that the surface of the matt CSWPU films was extremely rough and was comprised of many spherical particles with diameters in the range of 0.8–3.0 μm arranged on the films' surface. The matt CSWPU resin tended to have a relatively higher molecular weight and lower swelling ratio. Moreover, an increase of sulfonic hydrophilic chain-extending agent content or the initial molecular weight of the soft segment facilitated the improvement of thermal stability.

A facile and effective strategy for fabricating a tunable wettability surface on cotton fabrics by dip-coating into self-assembled fluoro-copolymer micelle of poly(hexafluorobutyl methacrylate)- b -poly(oligo(ethylene glycol) methyl ether methacrylate) is developed. The micelle solution, exhibiting thermal-responsive property with uniform spheres at 20 °C and irregular particles at above 50 °C, shows switchable wetting behaviors at different dipping and drying temperatures due to the changeable chemical structure of responsive polymer on fibers. The cotton fabric processed in cold micelle is smooth caused by the self-assembled structure of thermal-responsive micelle with fluorinated parts on the outmost fiber-layer, and it also has high fluorine content and good hydrophobic property. While the one treated in hot micelle is rough, and has good hydrophilic property due to the outmost layer of hydrophilic PEG segments on fibers. This work provides a simple strategy to construct controllable wettability surface and makes a great application potential in household commodity, industrial products and other smart complex materials.

A series of well-defined thermoresponsive graft polymers with different lengths and graft densities, poly(glycidyl methacrylate)-graft-poly(N-isopropylacrylate) (PGMA-g-PNIPAM), were successfully prepared by combination of controlled/living free radical polymerization and click chemistry. Effects of grafting length and density on the thermoresponsive behavior, aggregating mean diameter, and self-assembly morphology are systematically investigated. The thermosensitive characteristics of graft polymers in aqueous solution prove that the length and graft density had positive co-relationship with the lower critical solution temperature value and mean diameter of micelles as well as the size distribution, while the effect of graft length of polymers is more significant than that of density. Transmission electron microscopy analysis shows that the conformations of PGMA45-g-PNIPAM20 and PGMA45-g-PNIPAM46 with longer length and bigger grafting density in aqueous solutions are spherical nanoparticles with the increasing trend of the diameters, while that of PGMA45-g-PNIPAM(73, 50%) shows a spherical-like morphology, which indicates that the graft length and density have a significant effect on the mean diameter of micelle but not on the self-assembly morphology. These results reveal that to obtain desired thermoresponsive behavior and self-assembly morphology of functional polymers, it is essential to design and fabricate the structure of graft polymers with proper length and graft density. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014, 52, 2442–2453